A two-tier modified starch-oxidation followed by n-octenyl succinylation as gum Arabic substitute: Process details and characterization

Corn starch was oxidised using sodium hypochlorite to enhance its film forming property and reduce viscosity. This oxidised starch (OS) was further modified by n-octenyl succinic anhydride (OSA) to introduce hydrophobicity. This dual modified starch (OS-OSA) was characterized for crystalline and thermal attributes. The emulsion stability, viscosity and particle size of OS-OSA based emulsion with 60% soybean oil loading was compared with OS and gum Arabic (GA). The spray dried microcapsules using OS-OSA and GA as wall materials at 20% (w/v) containing emulsions demonstrated similar surface morphology (smooth surface devoid of cracks) and particle size. Microencapsulation with OS showed lower encapsulation efficiency (13%) than those with OS-OSA and GA (similar at 58%). The half-life of OS-OSA (39 weeks) microcapsules was lower than GA (44 weeks) but the final encapsulation efficiency after 18 weeks was similar in both cases. Thus OS-OSA corn starch can potentially replace gum Arabic for microencapsulation applications.